Electromagnetic switch



May 21, 1929. B. E.'GETCHELL 1,714,085

ELECTROMAGNETIC SWITCH Original Filed Sept; 22 1927 s Sheets-$heet l y 21, 1929- B. E. GETCHELL 1,714,085

ELECTROMAGNETI C SWITG H Original F iled Sept. 22, 1927 s Sheets-Sheet 2 I EELL- INVENTOR 5 Ben amJn E.

May 2'1, 1929. B. E. GETCHELL 1,714,085

ELECTROMAGNETI C SWITCH OI iginal Filed Sept. 22, 1927 S SheetS-Sheet 5 Fig. 7- 63 49 76 50 75 46 55 Benjamin L. 815011811,

Patented May 211, i929.

BENJAMIN E. GETCHELL, F PLAINVILIIEECCNNECTICUT, ASSIGNOR TO THE TRUM- ZBULL ELECTRIC MANUFACTURING COMPANY, OF PLAINVILLE, CONNECTICUT, A.-

CORZEORATION OF CONNECTICUT.

ELECTROMAGNETIC SWITCH.

Original application filed September 22, 1927, Serial No. 221,215. Divided aud this application filed December 27, 1927.

This invention applies particularly to the class of electric switches and similar devices in Which an electromagnet and an armature are arranged to cooperate, under certain circuit conditions,'to open or close a circuit or to operate co-related parts of the construction. Devices of this class are usually built up of a comparatively large number of parts l0-mounted on a base-being supported by a frame or its equivalent which isin turn se-' cured in an enclosing box. The magnetically operated armature moves rapidly and stops with considerable impact 1 against the magnet or some part of the construction provided for that purpose. Such constructions usually-include a considerable number of screws for holding the parts in position in addition to the usual screws for connecting the circuit wires and the repeated stopping impact of the magnetically operated memberv against any part of the construction tends to loosen the .parts, especially the screws. An important object of my invention is to guard against such danger by providing a construction which will allow for the full and complete movement of the magnetically operated parts in such a manner that the op erating impact will not be transmitted to the screws or other correlated parts. p

Another object is to provide simple but compact and reliable construction of the character described.

The particular object of my invention is to provide amagnetically operated switch hav ing means for absorbing the operating. shock. in sucha inanner that the shock or vibration will not be transmitted to the screws or. other parts which ordinarily might become loosen'ed by the repeated operations of the switch.

In the specific form shown herein, the armature is arranged to be moved-to effect the desired result although in some cases. it may be desirable to provide a movable magnet coil to cooperate with a relatively stationary armature but, in either case, it is my purpose to provide for a certain relative movement between the magnet and its cooperating armature. In reducing my invention to actual practice, I preferably provide an electromagnet (together with its core and pole pieces as a Serial No. 242,558.

unit) with a form of mounting which will permit a limited free movement and a cooperatingmovable armature which has an operable connectionwith movable switch contacts or 'other'parts which are to be operated.

The magnet unit, the armature, and the switch contacts are so co-related that, when the armature is attracted by the magnet, it will cause asimultaneous movement of the switch contacts and, when the armature strikes against the poles of the magnet unit, the free movement mounting of the latter will permit it to'move in response to the impact ut, due to this free movement mounting, no shock or impact will be transmitted to the screws or other parts of the construction. In other words, the operating shock of the armature Will be absorbed by the magnet unit because of its free movement mounting. After receiving the operating impact of the armature, the magnet will return to its normal position by gravity alone'or it may be assisted by suitable spring means. 7

The contacts and relays are supported on the front of the insulating base and the electromagnetic operator is mounted behind the base. When the armature has completed its movement and rests against the pole pieces of the magnet, it remains in that position against the tension of the spring contacts which will operate to cause a rapid separation of the armature from the magnet when the circuit is broken. These spring contacts also operate to move the magnet unit back into its normal position as it stood before being struck by the moving armature.

The foregoing describes the basic ideas of the invention but, in practice, certain refine- I ments of detail are desirable. For instance,

it is desirable that some of the shock of the" fast moving armature be absorbed by a suitable'yielding ineans before the armature actually-strikes against'the oles of the magnet and it is also desirable tliht the switch con tacts close with a yielding pressure. These two requirements are provided for by using spring contacts which engage the corresponding stationary contacts before the armature reaches the poles of the magnet and, for the.

reason that thespring contacts are connected with the armature,the closing impact of the latter is checked.

' 221,215, filed Sept. 22,1927.

' form of mechanism embodying improvements of my invention.

This is a division from my application No;

' The accompanying dra' gs show one Fig. 1 is "a. fi'ont' view (if the construction but omittingtherelay elements.

nary 12, 1926.

' Fig. 2 is a side view showing ee er the relays preferably intended to be used with the constructionr- Such a relay is shown my former Patent hlo. 1,559,36gt, dated '3 an- Fig. 3 isa perspective'view showing the connecting links between the armature and l the right hand side plate being omitted and partsbeingjshown in section.

r and 17 are-of metal and provided wit flanges ju shown in section.

the movable switchmember. r Fig. 4'is a view from the right hand side,

Fig. '5 is a'vertical sectional view.

Fig. 6 is afront view omitting base and parts being broken away. r

Fig. 7 "s a view looking upward at thelower Fig. 8 is a rear view, some of the parts he The baseorbody 15, may be-formed o fin sulating material, suchas molded composi.-' tion.- .Inlthe form shown. the; side lates 16 which are secured to the hasebyscrews, such as'18' and 19. The back plate20 may be se--.

7 cured to the side plates by screws such as 21.

. This particular form of back plate is adapted v I for convenientattachment' to aback boardor aswitch box (not shown) For convenience this .back' plate 20,is provi de ,d with a;

' z-keyhole slot -22 at the top bymeans of which it may be eonveniently-hungon a screw (not shown). The lower corners of this'plate 20 are provided with notches 23 anaee which open toward one side and toward'thebottom for convenience in mountin theplate under *thelheads of screws (not; ownli nnnene closmgbox.

,Thelineterminal's 25,26 remains ed on the front face of the base along its lower edge. The'load terminals 28, 30am mounted in the same planealong the upper edge of the base; The terminals 31, 32 and 33'aidapted to be connected to a control station'or switch-are mounted along'zthe uppJer edgeofthe base at its rear. Theload may 9,.

for-instance, a'motor (not shown) The switch has three c1rcu1t controlling;

units'in the particular form shown." "The lefthand' unit has stationary contacts 35 and 36- and a movable switch-member like 72 (Fig, 5)

I composedoicontactmembersand connected,

" together'bfa'flexible strip which inayfbei formed of thin laminations so thatfthe two;

' 'contaetmembers are free to tilt androckso as-to assure perfect contact withftlie'raised =mirtions 40.and 41 vofthe stationary contacts 'Tliefhamkjilate42 has its ends offset from may be readilyremo 5 desired by the simple operat1on of pressrng, down upon the washer and turning it with j to 'those previously \described. Thvcentral' '65" to fit the clipsii3and 65 andan interme- A cross-connectingcontact 85 i s and 87. c p v nected-respectivlyto the control sw tch-ter- 139 with bosses adapted to restiagainst Q the back-of the connecting strip 39 so as to permit relative tilting ofthe contact pieces '37 and 38. Theinovable contact parts just described and the corresponding. movable .con-

tacts rfor-theother switch units are all car iried by the, insulating member 45 whj h tends across'the base of the switch in th f r r er a cross barl This cross barhas'set ,-in.it aiiatstud 4J5, the end-of which ezttends 46. this way theggnovable contact parts 1 The upper contact 35 of the left hand switch unit is electrically and mechanically secured 85 to the terminal 28 by a screw 54. The lower contact 36 is secured to the clip forthe re- Y lay 56, The lower c1ip57 for the relay is electricallyand mechanically connected to the lower terminal 25 by. screw-58 which may be seated in'asuitableinsertfin'the base in any suitable manner. The-intermediate cli 59' .for the relay simjiarly se'curedto the ass. "The right hand switchis constructed in the same manner as the one previouslyde;

and for the relay 66 are similarly mounted switch unit also hasstationary contacts 70 and 71 and a'movable contact- 7 2. This unit, however, requires no relay and hence the con tact v71 is,cgi'rilile'cted directly 'to the terminal diate terminal "64' to'engage clip 64 of a suit able relay havin an automatm'thermpstatic I circuit breaker: notishown) for instance as? shovinlinjin .iormerpatents.

The base 15 is provided with a transcontacts of each-respective pair of the stationary contacts. The bas'ezis also grooved at 78 nd 7 9 to receive the ends of the flanges of the. switchfcarrier 45 are providedwith propecting lu 80 and 81 which are movably mounted in grooves'82 and 83 inthe side plates 17'and16' respectively; A

in"the-back'of.the cross bar45 andadapted to connect the resilient contact members 86 The two =-latter' "contacts are con- 75' I through a spring 49 andva cupflikewasher 50: This washer has a central slot, 51 "to pjermit it to he" slipped on to the end of the-stud "I d and-replaced when 8 951' scribed and has stationary contacts 60 'a'ndi61j and a' movable c9nta'3et62; Relay clips. 63, 64

.75 an 76, ,respe fiY y he pP ends V 5 mounted min-als 32 and 33 and the operation will be explained hereinafter. At the back' of the'base is mounted an electromagnet and armature. Thismagnet has a coil 90 one terminal of which is connected to the control switch terminal 31 and the other terminal of the coil is connected to the intermediate clip 59 for the left hand coil constitute a vertically movable magnet frame or member. The armature 94 may also be laminated and movable vertically with respect to the magnet-coil and core. The armature is connected to the insulating cross bar or contact carrier by a link motion which is supported. by the side plates 16 and 17.

Lever plates 95 and 96 of substantially bell crank form are pivoted to the side plates 17 and 16 respectively, and connected to the lugs and 81 of the insulating crossbar by links 97 and 98. Extending from these levers 95 and 96 are connecting rods 99 and 100, the lower ends of which are connected to the ends of the cross bar lOl-which carries the armature 94. The connecting rods and links 99 and 100 may be guided between lugs or projections 102 and 103 formed in the side plates 16 and 17.

When the'magnet is energized it lifts the armature 94 and, through the medium of the connecting links 99 and 100, tilts the lever plates 95 and 96, and thus through the pull of the links 97 and 98 draws the contact car rier 45 toward the base so as to cause the movable contacts to engage the stationary contacts. On account of the inclination of the guide slots 82 and 83 the movable contacts slide upwardly on the stationary contacts until fully seated, thus affording a sliding or wiping contact which insures perfect electrical connection. As the contact carrier 45 is drawn backward and upward toward the base, the springs 49am compressed, thus insuring an even pressure between the contacts and. affording a yielding engagement which prevents shock to the parts of the switch. As the cross piece engages the re [silient contacts '86 and 87 additional resiliency is provided to bring the parts to rest without shock. In the form shown the electromagnet is vertically movable being guided in the slots 93 so that even the inertia of the moving armature cannot apply a' direct blow on the stationary parts of the mechanism.

The magnet circuit may be closed or openedin any suitable manner.

In caseof overload the magnet circuitwill automatically be opened through one or both of the relays' In case of failure of line voltage or abnormal drop of line voltage, the magnet .Will become weakened and unable to hold the armature against gravity and the force of. the springs and the armature will drop away from the magnet thus opening the load and magnet switches. After the switch is once opened, it cannot normally be closed again except byiarcmote switch or equivalent. This feature is of great value in that it protects the operator against the unexpected starting ,of the motor or other device after it has once been stopped.

Although I have described the preferred form'of the complete apparatus and its meth- 0d. of operation, it should be understood that someof the features may be employed independent-1y of others, for instance, the shock absorbing'features herein set forth. are applicable to other'types of switches, so also it should be understood that the invention is not limited to the use of the particular thermostatic relay herein set forth. It should also be understood that although I have described the invention as particularly applicable to control from a remote point, certain features may be employedwithoutsuch limitations, forinstance, in some cases the con trol buttons may be mounted directly upon the box which encloses the main switch. I intend that'theclaiins shall be interpreted broadly as the may appear except asr may be required by t e stateof the art or by the terms thereof.

- I claim:

1. In anelectric switch,'a movable switch member, an electro-magnet and an armature both of which are slidably mounted and vertically movable and one of which is operably connected to said switch member and shock. absorbing means forsaid magnet members.

2. An electric switch including a frame,

a magnet mountedto slide in the frame, an armature for the magnet mounted to move in the same direction as the magnet with the magnet and independently thereof, stationary and movable contact members one of which is resilient, and means of connection bet-ween the armature and the movable contact member.

3. An electric switch including a frame having side plates, a magnet having a cross bar guided to slide in the side plates and supported therein. an armature for said magnet, links guided by the sideplates and connected to said armature whereby the armature is adapted to move toward and from the magnet and the magnet is adapted to more under impact of the armature, a stationary contact anda movable"contact, one of which is resilient, and means of connection between. said links and the movable contact.

4. In an electrically operated switch, both gravitational-means means ,for absoryn'gthe shock of closure, said gravitationa ans consisting of a vertically mov able magnet having an armature so mounted that the ma gagement et may 'move upward uponen- ,ith said armature, and said" spring means consisting of -yieldable contacts adapted to be moved by said armature.

' 5.- An electrically bperated switch mechaincluding a slidably supported magnet an armature coacting with, said magnet an .mounted so as'to move in the same direction as the magnet,-a pair of stationary contacts, a contact Qcarrier adapted to be moved by a. said armature, a pair of movable contacts yieldably supported upon said carrier for engagement with said stationary contacts,-

said carrier being adapted to approach said stationary contacts at an anglewhen actuated by'said armature so as to produce aslidiiig agement between-said movable contacts said stationary contacts and to cushion (the operating impact of saidarmature.

.1 amber 6. him electrically dprated switch; both gravitational means and spring means for absorbing the shock of closure, said. gravitational means consisting of aivertically movable magnet having a vertically movable armature, and said springmeans consisting o -y1eldab1e contacts adapted to be moved by said armature and serving as a resilient abut- A switch frame having guide slots, and I nient for said armature. v

ber guided between said lugs, a switch member actuated by one of said magnet members and a resilient stop'for said switch member.

' BENJAMN a GE'rcnELL. 

